make sure /firstpage hook code is executed before /lastpage hook code

base/ltshipout.dtx

@@ -33,7 +33,7 @@
 %
 %    \begin{macrocode}
 \providecommand\ltshipoutversion{v1.0g}
-\providecommand\ltshipoutdate{2021/01/12}
+\providecommand\ltshipoutdate{2021/01/18}
 %    \end{macrocode}
 %
 %<*driver>
@@ -903,6 +903,13 @@
 %    \begin{macrocode}
               #3
 %    \end{macrocode}
+%    We then run \cs{@@_add_firstpage_hook:} that adds
+%    the content of the hook \hook{shipout/firstpage} to the
+%    start of the first page (if non-empty). It is then redefined to
+%    do nothing on later pages.
+%    \begin{macrocode}
+              \@@_add_firstpage_hook:
+%    \end{macrocode}
 %    Then we check if we have to add the \hook{shipout/lastpage} hook
 %    or the corresponding kernel hook
 %    because we have reached the last page. This test will be false for
@@ -921,13 +928,6 @@
                     \bool_gset_true:N \g_@@_lastpage_handled_bool
                 }
 %    \end{macrocode}
-%    We then run \cs{@@_add_firstpage_hook:} that adds
-%    the content of the hook \hook{shipout/firstpage} to the
-%    start of the first page (if non-empty). It is then redefined to
-%    do nothing on later pages.
-%    \begin{macrocode}
-              \@@_add_firstpage_hook:
-%    \end{macrocode}
 %    Finally we run the actual \TeX{} primitive for shipout. As that will
 %    expand delayed \cs{write} statements inside the page in which
 %    protected commands should not expand we first change \cs{protect}